1. Issue the query
2. Check the 10 top results
3. Make up for yourself that those results are currently satisfying the intent (and base your KW research on that search intent keywords)
4. Generate a content that, based on those results, satisfy that intent. Make 1 or 2 improvements, thinking that you could improve even further the intent.
5. Wait and see how your new content is ranking (at least 2 or 3 months)
6. Check the SERP results to see if the first results you saw are almost the same.
7. In case they have changed, change your site accordingly.
8. Rinse and repeat
Note: Sometimes the SERP is not 100% accurate and you may see in the 10 top results what is called "a mixed intent". Choose one of the main intents, don't try to go for all. Check after a couple of months to see if the mixed intent has integrated or if it stays the same
For example: "garden accesories", could be an informational intent or a buying intent, therefore a "mixed intent". You may see both pages with "informational content" or "e-commerces". Choose one of both, an informational content to write, or if your have an ecommerce, your garden accesory listing.
There is no rule of thumb for this. What Quality raters basically do, is check the multiple intents and suggest to Google the primary and secondary intents according to them.
But for a SEO pro, what primes is the CURRENT intent, not your HYPOTHESIS. Although you could try an hyphotesis and intent switch to it over the time,
from my point of view is too risky and a waste of time. You will nail it 1 out of 100 times at best.
The safest way to work on this topic is going by the
CURRENT INTENT theory.
TL;TR This:
Search your keyword and check the top results.
Those are the "answers" that are matching the intent for the keyword.